Pressure relief device

ABSTRACT

AN ACCUMULATOR IS PROVIDED IN A LIQUID FUEL DISPENSING APPARATUS, SERVING AS A NONLEAK PRESSURE RELIEF DEVICE, TO RELIEVE PRESSURE INCREASES WHICH MAY ARISE IN THE DISPENSING HOSE WHILE THE APPARATUS IS IDLE. THE ACCUMULATOR COMPRISES FLEXIBLE PARTITION MOUNTED WITHIN A CHAMBER AND MOVING   BACK AND FORTH IN RESPONSE TO DIFFERENCES IN THE PRESSURES APPLIED TO THE TWO RESPECTIVE SIDES OF THE PARTITION.

United States Patent Inventor Einar T. Young Newtown Square, Pa. Appl. No. 855,849 Filed Sept. 8, 1969 Patented June 28, 1971 Assignee Sun Oil Company Philadelphia, Pa.

PRESSURE RELIEF DEVICE 6 Claims, 3 Drawing Figs.

U.S. Cl 137/551, I38/30 Int. Cl ..Sl6k 37/30, S 1 6i 55/04 Field of Search I 37/55 I 557, 559; 222/52; 73/l95, I98, I99, 201, 202. 304; l38/30 [56] References Cited UNITED STATES PATENTS 3,l24,l56 3/l964 Eskin et al. 137/559 3,318,328 5/1967 Schrader l37/557 3.352,488 ll/l967 Greene l37/55IX Primary Examiner-Henry T. Klinksiek Attorneys-George L. Church, Donald R, Johnson, Wilmer E.

McCorquodale, Jr. and Frank A. Rechif ABSTRACT: An accumulator is provided in a liquid fuel dispensing apparatus, serving as a nonleak pressure relief device, to relieve pressure increases which may arise in the dispensing hose while the apparatus is idle. The accumulator comprises a flexible partition mounted within a chamber and moving back and forth in response to differences in the pressures applied to the two respective sides of the partition.

PATENTEB JUN28 |97l SHEET 1 OF 2 INVENTOR: B EINAR T. YOUNG ATTy,

PRESSURE RELIEF DEVICE This invention is concerned with liquid fuel dispensing ,apparatus, such as may be employed in service stations for dispensing liquid fuel from an underground storage tank into the fuel tank of a motor vehicle.

My copending application, Ser. No. 805,901, filed Aug. 18, l969, now discloses a liquid fuel dispensing apparatus designed for simplified manipulation, and thus particularly suitable for a self-service type of operation. (For convenience, this application will be referred to hereinafter as the dispensing apparatus" application.) One of the features of this apparatus which contributes to the simplified manipulatability is the automatic dispensing nozzle disclosed in my copending application, Ser. No. 796,003, filed Feb. 3, 1969; this nozzle (being automatic) does not have a manually operated shutoff valve, in sharp contrast to the conventional nozzles in use at the present time. (For convenience, this last-mentioned application will be referred to hereinafter as the nozzle application.)

The hose of the dispensing apparatus always contains liquid, at the conclusion of each dispensing operation. While the dispensing apparatus is idle, the pressure in the hose often rises due to thermal expansion of the liquid, the presence of air bubbles in the hose, etc. If there is no manual shutoff valve in the nozzle (the manual shutoff valve if present being of course closed while the dispensing apparatus is idle), this pressure rise could cause liquid fuel (which may be gasoline) to flow out through the nozzle between dispensing operations (i.e., while the dispensing apparatus is idle). This latter action is undesirable from the safety standpoint, and also from the standpoint of Weights and Measures standards, whichlatter necessitate that the hose be full of liquid fuel at the start. of each dispensing operation.

An object of this invention is to provide a nonleak pressure relief device for liquid fuel dispensing apparatus.

Another object is to provide a novel arrangement for preventing leakage of fuel from a fuel dispensing hose, upon a pressure rise in such hose.

A further object is to provide a novel type of accumulator, which is particularly suitable for use in gasoline dispensing apparatus.

The objects of this invention are accomplished, briefly,.in the following manner: An accumulator, comprising a diaphragm sealed into a chamber, serves to relieve excessive differences between the fluid pressures applied to the two opposite sides of the diaphragm. The pressure at the discharge side of the liquid fuel pump is applied to one side of the diaphragm, while any increase in the hose pressure is coupled to the other side of the diaphragm.

A detailed description of the invention follows, taken in conjunction with the accompanying drawings, wherein:

FIG. 1 is a vertical section through a manifold assembly according to the invention, together with a somewhat schematic representation of a blend control valve to which the manifold assembly is coupled;

FIG. 2 is a front elevation or face view of the manifold assembly, but omitting the blend control valve; and

FIG. 3 is a sectional view taken along line 3-3 of PK]. 2.

Referring now to the drawings, a cast housing, denoted generally by numeral 1, is mounted within the housing (not shown) of a liquid fuel dispensing apparatus by means of a mounting plate 2 secured within the dispensing apparatus housing, to which plate one end of the housingl is suitably secured. The housing 1 may be thought of as comprising a manifold assembly, and contains various internal passages, as will be described hereinafter.

The invention is particularly adapted for use in a multigrade motor fuel dispensing apparatus of the type disclosed in my dispensing apparatus" application, wherein two fuel com- .ponents of different octane ratings are separately pumped and metered, and are blended together at the dispensing nozzle in a selected ratio, or else a single one of the components is dispensed to the exclusion of the other. That is to say, the total number of grades which the apparatus is capable of dispensing comprises blends of the two components. as well as either one of the components, separately. The two fuel components are generally referred to, respectively, as a "lo" gasoline (meaning a relatively low-octane gasoline component) and a hi" gasoline (meaning a high-octane gasoline component). In the overall motor fuel dispensing apparatus, two manifold assemblies of the type to be described are utilized, one for the lo gasoline and the other for the hi" gasoline. Since these two assemblies are exact duplicates of each other, only one will be described herein, and for convenient reference this will be assumed to be the one for the 10" gasoline.

Speaking generally, and in accordance with the disclosures in both of my above-mentioned applications, the lo gasoline is pumped by a lo pump from a supply (storage) tank through a 10" meter and a lo check valve to the lok section of a-blend control valve, and then (as controlled by this valve section) through a 10" hose and a lo antidrain valve to a common mixing region adjacent the spout or outlet of the dispensing nozzle. Similarly, the hi" gasoline is pumped by a hi" pump from a separate supply (storage) tank through a hi" meter and a hi check valve to the hi" section of the blend control valve, and then (as controlled by this latter valve section) through a hi" hose and a hi" antidrain valve to the aforementioned common mixing region. If a blend of the hi" and lo gasolines is being dispensed, mixing of the two components occurs in this common mixing region and the resultant blend flows out the open end of the nozzle; however, if only one of the two components is being dispensed, the other section of the blend control valve is closed and only said one component appears in the mixing region and flows out the open end of the nozzle. The foregoing summary, of course, refers only to the time during which the dispensing apparatus is pumping or active; when the apparatus is idle both pumps are off, or not driven.

The manifold assembly for the lo gasoline is located in the flow path of the 10" gasoline, between the lo pump and the 10" section of the blend control valve, and includes (or has directly associated with it) the lo check valve and the 10 meter, plus a"lo" filter and plus a pressure relief device according to this invention. The manifold assembly for the hi gasoline is located in the flow path of the hi" gasoline, between the hi" pump and the hi" section of the blend control valve, and includes (or has directly associated with it) the hi check valve and the hi" meter, plus a hi" filter and plus a duplicate pressure relief device according to the invention.

The housing 1 is somewhat elongated in the vertical direction, and near its lower end has therein an L-shaped internal passage 3 one end of which opens into what may be termed the back face of the housing and the other end of which opens into the bottom face of the housing. A coupling member 4, having therein a passage 5 akin to that in a pipe elbow, is secured as by means of bolts 6 to the back face of housing 1, in such a position that one end of passage 5 communicates with the back-face end of passage 3, leakage at the joint between member 4 and housing 1 being prevented by an O-ring 7 located in a groove in member 4, around passage 5. The other end of passage 5, which points vertically downwardly in FlG. 1, has a sealing enlargement 8 into which one end of a pipe (not shown) may be sealed; the opposite end of this last-mentioned pipe is connected to the discharge side of the IQ gasoline pump. Thus, when lo gasoline is being dispensed, lo gasoline flows through passage 5 and into passage 3.

A plug member 9, having therein a longitudinally extending bore 10 whose upper end is enlarged, is secured as by means of bolts 11 within a vertically extending bore 12 provided in the lower end of housing 1, leakage at the joint between plug 9 and hosing 1 being prevented by an O-ring 13 located in a groove in housing 1, around bore 12. The outer or lower end of plug 9 has an externally threaded boss 14 to which is threadedly attached a lo" filter cartridge 15. The filter cartridge has a perforated open central sleeve 16 the upper end of which is threaded for attachment to boss 14 and, between this sleeve and the outer metal housing of the cartridge, an elongated annular (hollow cylindrical) mass of filtering material 17. The upper end of the filtering material 17 is directly exposed to the lower end of passage 3. When lo gasoline is being dispensed, this gasoline flows out the lower end of passage 3, and thence into and though the filtering material 17 into the interior of sleeve 16 and upwardly into the bore of plug 9. A certain small fluid pressure drop takes place between the inlet and the outlet of filtering 15. At its upper, open end, end, outer metal housing of cartridge carries a sealing means 18 (e.g., an O-ring) which seals against the bottom end of housing 1 and thus prevents leakage.

A member 19, whose lower end is of cruciform shape, is mounted for vertical sliding movement in the upper enlarged end of bore 10, to serve as the moving element ofa 10" check valve. The disc-shaped upper end of member 10 carries an O- ring 20 which is adapted to seal against an upwardly facing valve seat formed at the upper end of plug 9. Member 19 is biased downwardly by a weak compression spring 21 whose lower end engages the upper face of this member and whose upper end engages a horizontally extending internal surface in casing l. The member 19 acts as a check valve to permit fluid flow upwardly through bore 10 but to prevent flow downwardly through this bore. Fluid pumped upwardly through bore 10 overcomes the bias of spring 21 and lifts member 10 upwardly away from its seat, the fluid then flowing upwardly through the space thus provided; any fluid which may tend to flow in the reverse direction (downwardly) from above member 19 would force member 10 more tightly against its seat, thus preventing any flow in this latter direction.

Above member 19, housing 1 has an internal passage 22 which extends generally upwardly and whose lower end communicates (when member 19 is lifted away from its seat) with bore 10 and whose upper end opens into an aperture 23 in the back wall of housing 1. The aperture 23 provides an inlet coupling for a lo" meter 24 (illustrated somewhat schematically) which is suitably mounted (as at 27, FIG. 2) on the back face of housing 1. The 10" gasoline component, if flowing through housing 1, reaches meter 24 via inlet aperture 23, passes though this meter, and leaves the meter by way of an outlet aperture 25 in the back wall of housing 1. The meter 24, which may be of a conventional type, meters the quantity of lo gasoline component which passes therethrough, and provides a mechanical output proportional to the total gallons of such components which have passed therethrough during a dispensing operation. This mechanical output is utilized to operate certain registering and control instrumentalities (not shown), as disclosed in my dispensing apparatus" application.

The normal" or forward" direction of flow through meter 24 is from inlet aperture 23, through the meter, to the outlet aperture 25; any flow or leakage of gasoline through meter 24 in the opposite or reverse direction would be disad vantageous, and such reverse flow is obviated according to this invention, as will be described later. A certain drop in fluid pressure occurs between the inlet and outlet of meter 24.

Aperture 25 opens into a somewhat elongated and generally vertically extending internal passage 26 in housing I, at a location intermediate the ends of such passage. The lo gasoline which has flowed through meter 24 enters passages 26 by way of aperture 25, and flows upwardly in this passage to the upper end thereof, where it leaves via an aperture 28 provided in the front wall of housing 1, which last-mentioned aperture opens into the upper end of passage 26.

One end of a pipe 29 (shown somewhat schematically) is sealed into the aperture 28, this pipe serving to supply gasoline to the inlet side of the lo section ofa blend control valve 30, which is constructed and operated as disclosed in my dispensing apparatus" application. Although the valve 30 is illustrated in FIG. 1 as being located below mounting plate 2, such illustration is merely for the sake of convenience; actually, the blend control valve 30 is located, physically, some little distance above the mounting plate 2 within the housing of the dispensing apparatus, and in such a location that it can be mechanically operated by means of a crank 31 coupled to a link member 32, as disclosed in my dispensing apparatus" application. In the 10" section, illustrated, of valve 30, a shaft 33 serves to mount a valve shoe 34 which is provided with a cylindrical surface engaging the interior wall of a cylindrical chamber 35 in the valve housing or body 36. The shoe 34 cooperates with an outlet port 37 in the valve body for the control of flow of the lo" fuel component, the valve or housing end of a lo dispensing hose 38 being coupled to receive liquid flowing through this outlet port. The "lo" gasoline enters the chamber 35 by way of the pipe 29, leading from the manifold assembly housing outlet aperture 28 to the inlet port for chamber 35. It may be seen that by rotation of shaft 33, the shoe 34 may be made to selectively cover or uncover the outlet port 37, and thus to control (during dispensing) the flow of lo" gasoline into the hose 38.

it is pointed out at this juncture that a duplicate structure is used for the hi" section of blend control valve 30, as disclosed in my dispensing apparatus application.

The valve shoe 34 is capable of sliding movement lengthwise along a stub shaft 39 whose axis extends at right angles to the axis of shaft 33 and which is secured at one end to shaft 33. However, the rotation of shaft 33 about its axis, and with it stub shaft 39 produces a rotary movement of shoe 34 about the axis of shaft 33, causing this shoe to variably cover and uncover outlet port 37. The shoe 34 is biased outwardly along stub shaft 39, toward the interior wall of chamber 35, by a relatively weak coiled compression spring 40 one end of which bears against the inner end of shoe 34 and the other end of which bears in effect against the outer cylindrical surface of shaft 33.

The lo hose 38 may extend from the lo section of the blend control valve 30 to a dispensing nozzle (not shown) of the type disclosed in my nozzle application; in similar manner, a hi hose may extend from the hi section of the valve 30 to the dispensing nozzle. Such a nozzle has no manual shutoff valve, since it is designed for a simplified, automatic type of operation.

The major portion of the length of each of the dispensing hoses such as 38 lies outside of the housing of the dispensing apparatus, and these hoses are intended to, and do, remain filled with liquid between dispensing operations (that is, while the pumps are idle), due primarily to the provision of an antidrain valve for each fuel component, in the respective hose near the nozzle end thereof, as disclosed in my nozzle" application. While the dispensing apparatus is idle, the pressure in the hose or hoses may and often does increase above atmospheric pressure, as a result, for example, of thermal expansion of the liquid therein. If no pressure relief device were provided, this pressure increase would overcome the relatively weak spring pressure provided on the antidrain valve or valves, and gasoline would flow out the end of the nozzle, which for various reasons is quite undesirable.

As disclosed in my dispensing apparatus application, the vale shoe 34, and also the similar hi valve shoe, are closed over their respective outlet ports such as 37 at the end of each dispensing operation, and remain so closed between dispensing operations, while the pumps are idle. However, upon the occurrence of a pressure increase in one of the hoses such as 38, the force offered by the weak spring 40 is overcome, lifting the valve shoe 34 away from its outlet port 37 (in the direction of the axis of stub shaft 39), resulting in the transference of this pressure through the liquid in pipe 29 to the liquid in housing passage 26.

A cylindrical diaphragm chamber 41 is provided in the completely assembled manifold near the lower end of such manifold and at a location on the opposite side of the manifold longitudinal centerline from passages 5 and 3 (see FIG. 2), approximately half of this chamber being formed by a cylindrical recess provided in the back face of housing 1 and the other half being formed by a matching cylindrical recess provided in the forward face of member 4.

A flexible imperforate diaphragm 42, made of a synthetic rubberlike material which is substantially unaffected by gasoline, is mounted for movement back and forth within chamber 41 between two extreme positions one of which is defined by the circular bottom of the recess in member 4 and the other by the circular bottom of the recess in housing 1. The diaphragm 42 has the general shape of a hat when in its normal, unstressed position, and is mounted in chamber 41 by means of its annular flange or hat brim," which is positioned within a circular groove 43 in the forward face of member 4 and is clamped within this groove by the abutting faces of member 4 and housing 1.

An internal passage 44 provided in member 4 opens at one end into passage 5 (see particularly F IG. 1) and opens at its other end into the recess in member 4 which forms part of diaphragm chamber 41. The fluid pressure in passage 5 is applied (by way of passage 44) to one side of diaphragm 42, whichmay be thoughtof as the upper side in FIG. 3; let us denote this pressure by'A.

Below the meter outlet aperture 25, the passage 26 angles off laterally in housing 1 (so as to maintain it separate from passage 22; see FlG.'2) and continues downwardly toward the lower end of housing 1. At its lower end, passage 26 opens into the recess in housing 1 which forms part of diaphragm chamber 41. The fluid pressure in passage 26 is thus applied to the other side of diaphragm 42, which may be thought of as the lower side in FIG. 3; let us denote this pressure by B.

While the dispensing apparatus is in operation, the lo" gasoline pump creates a certain fluid pressure A which is greater than the fluid pressure B, due primarily to the pressure drops in the filter l5 and in the meter 24; in this connection, it may be recalled that the passage 5 is coupled directly to the discharge side of the lo gasoline pump. While so pumping, the differential pressure A-B effective on the diaphragm 42 may be approximately 5 p.s.i., and since the A or upper pressure is higher, the diaphragm would be at this time in the dotdash line (or lower) position shown in FIG. 3.

When the dispensing operation is completed, the lo" gasoline pump is turned off, so that the pressure A at its discharge falls to zero. While the dispensing apparatus is thus idle, pressure increasesin the lo" dispensing hose 38 may 'cause the pressure B to exceed the pressure A by from l to 3 p.s.i., so that the differential pressure B-A then effective on the diaphragm 42 may be from 1 to 3 p.s.i. Since the B or lower pressure is then higher, the diaphragm 42 would move toward the solid-line or upper position in Flg. 3, increasing the volume of the chamber 41 which is on the lower or B side of the diaphragm and thus relieving the excessive pressure. The fluid on the upper or A side of the diaphragm, chamber 41, is bled back to the pump via passages 44 and 5, and through the pump to the storage tank, when the diaphragm thus moves. It may be noted that, in moving from one position to another, the hat diaphragm 42 in effect pivots about its brim."

It may be seen, from the above, that the diaphragm 42 within its chamber 41 serves as a pressure relief device or accumulator, an accumulator being defined as a contrivance to take up the force of a sudden stain."

it may be noted that the pressure relief device of this invention bypasses both the meter 24 and the check valve 19, since one side of chamber 41 is coupled to the passage 26 beyond the meter outlet aperture 25 and the other side of this chamber is coupled to passage 5. (Bypassing of the check valve 19 would obviously be necessary in order to bleed gasoline back to the pump.) However since the meter 24 is bypassed, as well as the check valve, flow of gasoline through the meter in the reverse direction is obviated or avoided.

As previously mentioned, another manifold assembly which exactly duplicates the construction of the one described for the lo" gasoline, would be utilized for the hi" gasoline, in a multigrade gasoline dispensing apparatus. This other or duplicate manifold assembly would have its inlet side coupled to the discharge of the hi gasoline pump, would have its outlet side coupled to the hi" section of the blend control valve 30, and would have associated therewith a hi meter, a hi" check valve, and a "hr" filter. The hr section of the blend control valve would have its outlet port coupled to a hi" dispensing hose leading to the dispensing nozzle. The action of the pressure relief device or accumulator associated with such hi" manifold assembly would be exactly similar to that previously described for the lo pressure relief device 41, 42.

The accumulator or pressure relief device of this invention may be termed a nonleak pressure relief device, since the pressure increase (in the dispensing hose) is relieved without leakage of gasoline anywhere, no leakage out of the nozzle being pennitted to occur and the pressure being in effect relieved by bleeding of gasoline back to the pump.

lclaim:

1. ln liquid fuel dispensing apparatus, a pump having its intake coupled to a liquid fuel supply, said pump developing a positive pressure at its discharge side while in operation; a

hose connected to the discharge side of said pump through at least one flow-restricting device across which a pressure differential is developed during flow of liquid therethrough, an accumulator for the relief of excessive differences between the fluid pressures applied respectively to two functional couplings of said accumulator, means connecting one of said functional couplings to the discharge side of said pump, and means effective to apply fluid pressures developed in said hose, in excess of a preset minimum pressure, to the other of said couplings.

2. Apparatus according to claim 1, wherein said accumulator comprises a chamber, and a flexible imperforate partition mounted within said chamber; said two functional couplings being operatively associated with respective opposite sides of said partition.

3. Apparatus defined in claim 1, wherein said device com- .prises a meter for measuring the volume of liquid flowing therethrough.

4. Apparatus recited in claim 1, wherein a plurality of flowrestricting devices are located in the connection between said hose and the discharge side of the pump.

5. Apparatus defined in claim 1, wherein said device comprises a meter for measuring the volume of liquid flowing therethrough, and wherein said accumulator comprises a chamber, and a flexible imperforate partition mounted within said chamber; said two couplings being operatively associated with respective opposite sides of said partition.

6. Apparatus according to claim 1, wherein said accumulator comprises a chamber, and a flexible diaphragm sealed at is outer edge to the inner wall of said chamber; said two couplings being operatively associated with respective opposite sides of said diaphragm. 

